Drip emitter

ABSTRACT

A drip emitter is provided for delivering irrigation water from a supply tube to an emitter outlet at a reduced and relatively constant flow rate. Water enters the emitter through a first inlet and proceeds into a first chamber. When the water pressure is above a predetermined level, a one-directional valve opens to allow fluid flow past the first chamber, through a tortuous path flow channel, and through an emitter outlet. A second inlet is used to compensate for water pressure fluctuations in the supply tube to maintain output flow at a relatively constant rate. Water enters the second inlet and presses a flexible diaphragm toward a water metering surface to provide pressure-dependent control of the output flow. A copper member is mounted to the emitter over the emitter outlet to prevent plant root intrusion into the emitter outlet.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of pending U.S. patent application Ser.No. 11/359,181, filed Feb. 22, 2006, which is incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates to irrigation drip emitters, and moreparticularly, to subsurface irrigation drip emitters.

BACKGROUND OF THE INVENTION

Drip irrigation emitters are generally known in the art for use indelivering irrigation water to a precise point at a predetermined andrelatively low volume flow rate, thereby conserving water. Suchirrigation devices typically comprise an emitter housing connected to awater supply tube through which irrigation water is supplied underpressure. The drip irrigation device taps a portion of the relativelyhigh pressure irrigation water from the supply tube for flow through atypically long or small cross section flow path to achieve a desiredpressure drop prior to discharge at a target trickle or drip flow rate.In a conventional system, a large number of the drip irrigation devicesare mounted at selected positions along the length of the supply tube todeliver the irrigation water to a large number of specific points, suchas directly to a plurality of individual plants.

Subsurface drip emitters provide numerous advantages over drip emitterslocated and installed above ground. First, they limit water loss due torunoff and evaporation and thereby provide significant savings in waterconsumption. Water may also be used more economically by directing it atprecise locations of the root systems of plants or other desiredsubsurface locations.

Second, subsurface drip emitters provide convenience. They allow theuser to irrigate the surrounding terrain at any time of day or nightwithout restriction. For example, such emitters may be used to waterpark or school grounds at any desired time. Drip emitters located aboveground, on the other hand, may be undesirable at parks and schoolgrounds during daytime hours when children or other individuals arepresent.

Third, subsurface emitters are not easily vandalized, given theirinstallation in a relatively inaccessible location, i.e., underground.Thus, use of such subsurface emitters results in reduced costsassociated with replacing vandalized equipment and with monitoring forthe occurrence of such vandalism. For instance, use of subsurfaceemitters may lessen the costs associated with maintenance of publiclyaccessible areas, such as parks, school grounds, and landscaping aroundcommercial buildings and parking lots.

Fourth, the use of subsurface drip emitters can prevent the distributionof water to undesired terrain, such as roadways and walkways. Morespecifically, the use of subsurface drip emitters prevents undesirable“overspray.” In contrast, above-ground emitters often generate overspraythat disturbs vehicles and/or pedestrians. The above-identifiedadvantages are only illustrative; other advantages exist in connectionwith the use of subsurface drip emitters.

There is a need to provide for a relatively constant water output fromsubsurface emitters, regardless of fluctuations in the water pressure inthe supply tube. Without such flow rate compensation, water pressurefluctuations in the supply tube will cause corresponding fluctuations inthe emitter water output. Such fluctuations result in the inefficientand wasteful use of water.

There is also a need in the irrigation industry to keep subsurface dripemitters from becoming obstructed, which results in insufficient waterdistribution and potential plant death. Obstruction of an emitter mayresult from the introduction of grit, debris, or other particulatematter, both from debris entering the emitter through the supply tubeand debris entering the emitter from the terrain being irrigated, i.e.,“back siphoning.” Such obstruction of an emitter may result in severe,and in some cases complete, flow restriction, potentially preventing theemitter from operating entirely. Many irrigation systems depend on theoperation of each specifically situated emitter for sufficient watercoverage to maintain healthy grass, crop, or other plant growth.Accordingly, there is a need to prevent subsurface drip emitters frombecoming obstructed.

Further, there is a need to prevent obstruction of an emitter outlet byplant roots intruding into the outlet. Some conventional methods ofpreventing root intrusion, and the accumulation of microscopicorganisms, involve the use of herbicides, fungicides, algaecides,biocides, etc. For example, in some instances, herbicides have beenreleased indiscriminately into the soil in an attempt to prevent plantroot intrusion. Alternatively, herbicides have been mixed with theplastic materials from which the irrigation supply tube is made. Also,such chemicals have sometimes been mixed in dilute quantities with theirrigation water distributed by the tube.

These conventional methods are often not directed specifically to theemitters and emitter outlets and, therefore, may be of only limitedeffectiveness in preventing root intrusion. In addition, suchconventional methods generally target plants and the environmentindiscriminately and may have serious adverse effects on the health ofplants, as well as the broader environment as a whole. Accordingly,there is a need for a mechanism that is more targeted and moreenvironmentally friendly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of a drip emitter embodying features ofthe present invention;

FIG. 2 is a bottom perspective view of the drip emitter of FIG. 1;

FIG. 3 is a cross-sectional view of the drip emitter of FIG. 1 showingthe emitter mounted in an irrigation supply tube;

FIG. 4 is a bottom perspective view of the drip emitter of FIG. 1without the chimney feature;

FIG. 5 is an exploded perspective view of the drip emitter of FIG. 1;

FIG. 6 is a top plan view of the lower housing of the drip emitter ofFIG. 1;

FIG. 7 is another exploded perspective view of the drip emitter of FIG.1;

FIG. 8 is a top plan view of the drip emitter of FIG. 1;

FIG. 9 is an exploded cross-sectional view of the drip emitter of FIG. 1taken along line A-A of FIG. 8;

FIG. 10 is a cross-sectional view of the drip emitter of FIG. 1 takenalong line A-A of FIG. 8;

FIG. 11 is an enlarged partial cross-sectional view of the encircledportion of the drip emitter shown in FIG. 10;

FIG. 12 is a perspective view of portions of an alternate upper housingand lower housing embodying features of the present invention;

FIG. 13 is a top perspective view of the drip emitter of FIG. 1 withguide ribs for mounting the drip emitter;

FIG. 14 is a perspective view of the drip emitter of FIG. 1 without theoutlet shield being mounted to the drip emitter;

FIG. 15 is a perspective view of the drip emitter of FIG. 1 with theoutlet shield being mounted to the drip emitter;

FIG. 16 is a side elevational view of an alternate outlet shieldembodying features of the present invention;

FIG. 17 is a top plan view of a second alternate outlet shield embodyingfeatures of the present invention; and

FIG. 18 is a perspective view of a third alternate outlet shieldembodying features of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With respect to FIGS. 1-5, a drip irrigation emitter 10 is provided fordelivering irrigation water from a water supply conduit, such as anirrigation supply tube, at a low volume, substantially trickle, or dripflow rate. The emitter 10 operates generally through the use of atortuous path flow channel 38 that causes a pressure reduction betweenthe irrigation tube and an emitter outlet 22. The emitter 10 includes afirst inlet 16 for tapping a portion of the water flow from theirrigation tube, and, when the water pressure is above a predeterminedminimum level, directing the flow to and through the tortuous path flowchannel 38 for subsequent discharge to a desired location. In thepreferred embodiment, the emitter 10 also includes a second inlet 18 formaintaining relatively constant output water flow by compensating forfluctuations in water pressure in the irrigation tube.

The emitter 10 comprises a compact housing 12 made of a sturdy andnon-corrosive material. As shown in FIG. 1, the top surface 14 of theemitter 10 defines two sets of inlets, each including one or moreopenings extending through the top surface 14. The inlets are exposed tothe irrigation water flowing through the inside of the irrigation tube.

The first inlet 16 is shown in FIG. 1 and preferably includes threeopenings. Water flowing into the first inlet 16 proceeds through thebody of the emitter 10 to an emitter outlet 22. In traveling through theemitter 10 to the emitter outlet 22, water pressure is reduced and waterflow is reduced to a trickle or drip flow rate, as described in moredetail below. The three openings are preferably sufficiently small indiameter to perform a filter function for water flowing through thefirst inlet 16, i.e., to filter out debris or grit that might otherwiseclog the interior of the emitter 10. As shown in FIG. 1, the openingsmaking up the first inlet 16 are also preferably spaced in a triangularpattern to allow water to uniformly impact interior surfaces of theemitter 10. Although three equally spaced openings are shown in thepreferred embodiment, other numbers and arrangements of openings may beutilized to form the first inlet 16.

The second inlet 18 is shown in FIG. 1 as preferably including twoopenings spaced along a center axis bisecting the length of the emitter10. Water flowing into the second inlet 18 does not proceed through thebody of the emitter 10 but, instead, serves a pressure compensationfunction. As described below, water flowing into the second inlet 18accumulates in a chamber in the interior of the emitter 10, applyingpressure to the chamber in an amount substantially equivalent to thepressure in the irrigation tube. Because water flowing through thesecond inlet 18 does not flow through the emitter 10, the openings ofthe second inlet 18 need not filter the inflowing water and the openingsneed not be small in diameter. Although two openings are shown in thepreferred embodiment, as seen in FIG. 1, other numbers and arrangementsof openings may be utilized to form the second inlet 18.

FIG. 2 shows the base 20 of the emitter 10 with an emitter outlet 22,composed of at least one opening, extending through the base 20, andwith a raised rim 28 extending about the perimeter of the base 20.During assembly, a number of emitters 10 are mounted to the insidesurface 110, or wall 110, of an irrigation tube 100 at predeterminedspaced intervals with each emitter 10 oriented such that the raised rim28 of each is pressed into sealing engagement with the inside surface110 of the irrigation tube 100, as shown in FIG. 3. Thus, the raised rim28 of each emitter 10 is used to mount the emitter 10 to the insidesurface 110 of the irrigation tube 100 by acting as an attachment zone.Further, when the base 20 of each emitter 10 is mounted and the raisedrim 28 of each emitter 10 is bonded into sealing engagement with theinside surface 110 of the irrigation tube 100, a gap is formed betweenthe remainder of the base 20 (inside the perimeter) and the insidesurface 110 of the tube 100. The gap resulting from the mounting of theemitter base 20 to the tube wall 110 forms an outlet bath 34 for thedischarge of water from the emitter 10, as described below.

As shown in FIG. 2, the base 20 of the emitter 10 also preferablyincludes an elongated protrusion, or chimney, 26, which, in thepreferred embodiment, has an I-shaped cross-section. The chimney 26 isadapted to push outwardly against the tube wall 110 during assembly,thereby forming an area of the irrigation tube 100 that bulges outward.The outside of the tube 100 then passes under a cutting tool that cutsthe projecting tube portion and projecting end of the chimney 26 to forma supply tube outlet 120 that, in contrast to the emitter outlet 22,extends through the wall 110 of the irrigation tube 100. After cutting,as shown in FIG. 3, the remaining uncut chimney portion 27 extendsbetween the base 20 of the emitter 10 and through the tube outlet 120,allowing water to flow to terrain outside the tube 100. Morespecifically, water exiting the emitter 10 through the emitter outlet 22flows into outlet bath 34 and trickles out to the terrain to beirrigated through the elongated channels formed by the I-shapedcross-section of the remaining chimney portion 27 and through the supplytube outlet 120. The outlet bath 34 acts as an outlet conduit betweenthe emitter outlet 22 and the supply tube outlet 120 when the emitter 10is mounted inside the tube 100.

In the preferred embodiment, the chimney 26 is composed of an I-shapedcross-section. It should be evident, however, that the chimney 26 may becomposed of other cross-sections, such as a T-shaped or S-shapedcross-section. The cross-section need only be of a shape that willresult in elongated flow channels permitting fluid flow through thesupply tube outlet 120 when the protruding portion of the chimney 26 iscut off. For example, a chimney 26 having a solid circular cross-sectionwould not be desirable because it would completely obstruct the supplytube outlet 120 when cut off during assembly.

Further, in other embodiments, the chimney feature need not be used atall. In the preferred embodiment, the chimney 26 is used, duringassembly, to create an outlet 120 extending through the irrigation tube100 for each emitter 10. It should be evident, however, that there arealternative ways of creating such outlets 120. Thus, other embodimentsmay use alternative ways of forming outlets extending through theirrigation tube wall 110. FIG. 4 shows such an emitter 10 without achimney 26.

The emitter 10 is preferably of the shape shown in FIGS. 1 and 2, butmay be of any suitable size and shape to allow it to be mounted insidethe irrigation tube 100. The emitter 10 also preferably has roundedcorners 13 to reduce its profile with respect to water flowing throughthe irrigation tube 100. This profile reduces the force exerted byonrushing water acting to dislodge the emitter 10 from the insidesurface 110 of the tube 100.

As shown in FIGS. 5-7, the emitter 10 generally includes fourcomponents: an upper housing 30, a lower housing 32, a diaphragm 36, anda copper member 64. The upper housing 30 and lower housing 32 may beconveniently and economically formed from assembled plastic moldedhousing components. Although the preferred embodiment uses two separatehousing pieces assembled together, one integral housing piece (having alower housing portion and an upper housing portion) may also be used.The upper housing 30 is adapted for assembly with the lower housing 32to form a substantially enclosed housing interior, which encloses thediaphragm 36. A copper member 64 is preferably mounted to the undersideof the lower housing 32. The preferred embodiment uses smallercomponents and less material than conventional emitters, resulting incost savings.

The upper housing 30 includes the first inlet 16 and the second inlet18, each inlet including one or more openings extending through aportion of the upper housing 30. The lower housing 32 includes theemitter outlet 22, which extends through a portion of the lower housing32. Further, the lower housing 32 preferably includes the chimney 26,which projects away from the upper housing 30. The lower housing 32 alsoincludes raised rim 28 located about the perimeter of the lower housing32, the raised rim 28 defining outlet bath 34 when mounted to the insidesurface 110 of the irrigation tube 100.

The flexible diaphragm 36, interposed between the upper housing 30 andlower housing 32, is preferably a silicone or rubber membrane extendingcentrally between the housing portions. The diaphragm is preferablyshaped like a barbell and dimensioned to overlap and seal against thetortuous path flow channel 38 and water metering surface 42 of the lowerhousing 32. The diaphragm 36 has a first end 50 located beneath, and inflow communication with, the first inlet 16. The first end 50 defines avalve 40, which regulates flow from the first inlet 16 to the tortuouspath flow channel 38, as described below. The first end 50 of thediaphragm 36 extends into a central, elongated strip 37, which overlaysand sealingly engages the tortuous path flow channel 38. In turn, thecentral strip 37 extends into a second end 56 of the diaphragm 36, whichis located beneath, and is in flow communication with, the second inlet18. The second end 56 is preferably circular in shape to overlap andsealingly engage the water metering surface 42 of the lower housing 32.

The lower housing 32 includes an inlet end 44, the tortuous path flowchannel 38, and the water metering surface 42, which are formed on theinterior side of the lower housing 32. Water flows in the flow pathdefined by interior side of the lower housing 32 and the overlayingdiaphragm 36. More specifically, water enters the inlet end 44, flowsthrough the tortuous path flow channel 38, and flows through the watermetering surface 42 to the emitter outlet 22.

The tortuous path flow channel 38 preferably includes a number ofalternating, flow diverting ribs 60 projecting partially into the flowchannel 38 and causing frequent, regular, and repeated directionalchanges in water flow. Accordingly, the water flow takes on a back andforth zigzag pattern. The tortuous path flow channel 38 causes arelatively significant reduction in water pressure. In contrast, thewater metering surface 42 is responsive to more subtle fluctuations inwater pressure in the irrigation tube 100.

With reference to FIGS. 9-11, the valve 40 is preferably a check valve,or other one-way directional valve, and is positioned between the firstinlet 16 and the inlet end 44 of the tortuous path flow channel 38. Thevalve 40 is open and permits water flow between the first inlet 16 andthe emitter outlet 22 when the supply water pressure is above apredetermined minimum level, such as 5 psi. The valve 40, however,closes off the flow path through the emitter 10 when the water pressurefalls below the predetermined minimum level, as may occur when anirrigation cycle is completed. Closing the flow path through the emitter10 prevents the water in the irrigation supply tube 100 from slowlydraining to the outside through the emitter 10 and prevents backflowfrom entering the tube 100 from the emitter 10. Closing the flow pathalso prevents back siphoning into the emitter 10, i.e., closing the flowpath prevents dirt and debris from outside terrain from entering andclogging the emitter 10.

As shown in FIGS. 9-11, the valve 40 includes a tubular or cylindricalportion i.e., a boss 48, of the diaphragm 36 seated on top of asubstantially conical frustum portion 49 of the diaphragm 36. The boss48 is spaced downstream of the first inlet 16 and is hollow, defining ahole 46 in the diaphragm 36. The boss 48 sealingly engages the upperhousing 30 to block the flow path through the emitter 10 and, as shownin FIG. 11, disengages from the upper housing 30 to open the flow pathand allow water to flow into the inlet end 44 and tortuous path flowchannel 38. The inside surface of the upper housing 30 opposing the boss48 includes a projecting disk 53 that is received in the opening 52 ofthe boss 48. The disk 53 assists in guiding and aligning the engagementbetween the boss 48 and the inside of the upper housing 30 to ensure anadequate sealing engagement.

More specifically, water flowing through the emitter 10 presses down onthe pressure-sensitive and substantially conical frustum portion 49, orsnap button 49, which, in turn, if the water pressure exceeds thepredetermined minimum level, flexes, or “snaps down,” causing the upperend 52 of the boss 48 to disengage from its sealing engagement with theupper housing 30 and thereby opening the flow path through the diaphragmhole 46, as shown in FIG. 11. If the water pressure does not exceed thepredetermined level, the snap button 49 does not snap down, the upperend 42 of the boss 48 remains engaged to upper housing 30, and the flowpath through the diaphragm hole 46 remains obstructed. Thus, the snapbutton 49 operates between two positions—a raised position, in which theboss 48 is sealingly engaged to the upper housing 30, and a loweredposition, in which the boss 48 is disengaged from the upper housing 30.

In the preferred embodiment, the boss 48 is shown as seated atop thesnap button 49. In alternative embodiments, the boss 48 need not beseated atop the snap button 49. Instead, the boss 48 may be locatedadjacent to the snap button 49, or may be otherwise operatively coupledto the snap button 49, such that when the snap button 49 flexes, orsnaps down, in response to fluid pressure, the upper end 52 of the boss48 disengages from a portion of the upper housing 30.

As shown in FIGS. 5 and 6, the lower housing 32 preferably includes aC-shaped rib 45 near the inlet end 44 of the tortuous path flow channel38. The C-shaped rib 45 is located beneath the snap button 49 of thediaphragm 36 and prevents the valve 40 from being fixed in an openposition. More specifically, as shown in FIG. 5, the C-shaped rib 45projects away from the interior side of the lower housing 32 such thatit comes into contact with the snap button 49 when the snap button 49flexes downward in response to fluid pressure above the predeterminedminimum level. The C-shaped rib 45 prevents the snap button 49 fromflexing any further, thereby preventing the snap button 49 from becomingfixed in a lowered position and preventing the valve 40 from becomingfixed in an open position. Although, in the preferred embodiment, thesupporting structure beneath the snap button 49 is in the form of aC-shaped rib 45, it should be evident that the supporting structurecould be a differently shaped rib or a different supporting structuresuch as to prevent the valve 40 from becoming fixed in a loweredposition.

Water flowing through the irrigation tube 100 enters the emitter 10through the first inlet 16. It then enters a first chamber 58 defined,at least in part, by a portion of the upper housing 30, the boss 48, andthe snap button 49. The boss 48 initially is in sealing engagement witha portion of the upper housing 30 to block the flow channel through thediaphragm hole 46. If the pressure of water flowing into the firstchamber 58 and impacting the snap button 49 is below a predeterminedminimum level, the boss 48 remains in sealing engagement with the upperhousing 30, which, in effect, acts as a valve seat. If, however, thepressure of water flowing into the first chamber 58 and impacting thesnap button 49 is above the minimum level, the upper end 52 of the boss48 disengages from the upper housing 30, thereby opening the flowchannel through the diaphragm hole 46.

Water then flows through the hole 46 in the diaphragm 36 to the inletend 44 of the tortuous path flow channel 38. The water then experiencesmultiple directional changes as it is constantly redirected by theflow-diverting ribs 60 defining the tortuous path flow. This repeatedredirection significantly reduces the water pressure and water flow bythe time the water reaches the outlet end 54 of the tortuous path flowchannel 38. The water then flows through the water metering chamber 41,as described further below. Next, the water proceeds through the emitteroutlet 22, though the outlet bath 34 (defined by the region between thebase 20 and the inside surface 110 of the irrigation tube 100), and outthrough the supply tube outlet 120 (an opening defined by the tube wall110 and the I-shaped cross-section of the chimney 26). The water exitsthrough the supply tube outlet 120 to the terrain and vegetation outsidethe tube 100. Once an irrigation cycle is complete, or if the waterpressure in the irrigation tube 100 otherwise falls below thepredetermined minimum level, the boss 48 in the diaphragm 36 returns toit relaxed state, closing valve 40 and creating a seal to preventdrainage and back siphoning through the emitter 10.

The water metering surface 42 is shown in FIGS. 5, 6, 9, and 10. Thewater metering surface 42 is formed in the lower housing 32 and isgenerally circular in shape when viewed from the upper housing 30. It islocated downstream of the outlet end 54 of the tortuous flow pathchannel 38 and is upstream of the emitter outlet 22. As shown in FIG. 6,the water metering surface 42 includes a groove 43 formed therein forregulating water flow to the emitter outlet 22.

The water metering surface 42 is part of a pressure compensationmechanism for the emitter 10. Water initially flows through the secondinlet 18 and accumulates in a pressure compensation chamber 62 (FIG.10). The chamber 62 is defined by the upper housing 30 and the circularsecond end 56 of the flexible diaphragm 36 that overlays the watermetering surface 42. Water flowing into pressure compensation chamber 62accumulates in the chamber and does not flow through the rest of theemitter 10. In other words, the pressure compensation chamber 62 issealed from the rest of the emitter 10. As the water accumulates, thewater in the chamber 62 changes pressure with the pressure of the watersupply in the conduit 100 and presses down, accordingly, against thecircular second end 56 of the flexible diaphragm 36, thereby flexing anddeflecting the diaphragm 36 toward the water metering surface 42.

The water metering surface 42 and the overlaying diaphragm 36 form awater metering chamber 41, located beneath the pressure compensationchamber 62. During operation of the emitter 10, water pressure in thepressure compensation chamber 62 causes the diaphragm 36 to flex betweena fully relaxed position and a fully distended position, changing thesize of the water metering chamber 41. In turn, this change in size ofchamber 41 regulates water flow. More specifically, when the diaphragm36 is in a fully relaxed position, the water metering chamber 41 isrelatively large in size, allowing a relatively large fluid flow throughthe chamber 41. In contrast, when the diaphragm 36 is fully distended,the water metering chamber 41 is relatively small in size, allowing arelatively small fluid flow through the chamber 41. Thus, fluid flowthrough the water metering chamber 41 is reduced in general proportionto the amount of pressure exerted against the circular second end 56 ofthe diaphragm 36.

Further, the water metering surface 42 includes a groove 43 forregulating fluid flow. As shown in FIG. 6, the groove 43 has a depressedannular portion 55 that extends about the circumference of the watermetering surface 42 and a depressed radial portion 57 connecting a pointalong the annular portion 55 to the emitter outlet 22. When thediaphragm 36 is fully distended by relatively high pressure, it isdeflected into and presses against the water metering surface 42. Thegroove 43 provides a flow path along the depressed annular portion 55 tothe depressed radial portion 57 and out through the emitter outlet 22.The groove 43 allows output flow even at relatively high water pressure,such that deflection of the diaphragm 36 does not completely obstructfluid flow through the water metering chamber 41. Thus, the diaphragm36, water metering chamber 41, water metering surface 42, and groove 43act as a pressure-dependent mechanism to offset fluctuations in waterpressure in the irrigation tube 100 to maintain the flow rate throughthe emitter 10 at a relatively constant level.

The use of the flexible diaphragm 36 and the groove 43 also permit theflushing of debris and grit out of the emitter 10. If grit or debrisbecomes lodged in the flow channel of the groove 43, water pressure inthe groove will increase. When the pressure reaches a certain level, theflexibility of the diaphragm 36 allows it to be pushed upward, therebydislodging the debris.

As should be evident, numerous variations in the upper housing 30 andlower housing 32 are available to assure ease of assembly and ease ofmounting the emitter 10 to the inside wall 110 of the supply tube 100.For example, as shown in FIG. 12, the upper housing 30 preferablyincludes a flange 31 that extends about the perimeter of the upperhousing 30, and the lower housing 32 preferably includes a lip 33 thatprojects outwardly and defines the perimeter of the lower housing 32.The flange 31 and lip 33 engage one another to hold the upper housing 30and the lower housing 32 securely together. More specifically, theflange 31 of the upper housing 30 is preferably fused to the lip 33 ofthe lower housing 32, such as by melting or by other coupling methods,to hold the two housing pieces securely in place.

In addition, as shown in FIG. 13, the upper housing 30 preferablyincludes features to assist in mounting the emitter 10. Morespecifically, the upper housing 30 preferably includes two guide ribs105 for mounting each emitter 10 to the inside wall 110 of the supplytube 100. As shown, these guide ribs 105 project from the upper housing30 and preferably extend longitudinally near the center of the upperhousing 30, although other orientations and arrangements of guide ribsmay be used. During assembly, each emitter 10 is mounted to the insidewall 110 of tube 100, as shown in FIG. 3. More specifically, aninsertion device (not shown) presses against the upper housing 30 ofeach emitter 10 such that the lower housing 32 of the emitter 10 engagesthe inside wall 110. The guide ribs 105 provide stability and maintainproper orientation of the emitter 10 during mounting of the emitter 10by engaging corresponding ribs of the insertion device.

As shown in FIGS. 14-18, a copper member 64 is preferably used at theemitter outlet 22 to prevent plant root intrusion. Use of copper iseffective because, although copper is a required nutrient for plantgrowth, excessive amounts of copper inhibit root cell elongation. When aplant root comes into contact with copper, the surface of the root isdamaged, the root hairs die off, and the overall growth of the root isstunted. The copper, however, does not cause any serious damage to theplant itself. Because the copper remains in the plant's root tissue, itonly inhibits growth of the roots in close proximity to the copper anddoes not affect the overall health of the plant.

The interaction between copper and plant roots is used to protect theemitter 10 from root intrusion and obstruction of the emitter outlet 22.A copper member 64 is located in front of the emitter outlet 22 in orderto inhibit root growth into the outlet 22. The amount of copper that istaken up by plant roots is infinitesimal, and therefore, the life of thecopper member 64 is extremely long.

One cost effective form of a copper member 64, shown in FIGS. 14 and 15,is a thin rectangular copper plate 66 having two holes 68 and 70therethrough. The copper plate 66 is preferably compression fitted tothe base 20 of the emitter 10, such that the base 20 holds the copperplate 66 in place. The first hole 68 also is preferably dimensioned toreceive a locator peg 72 protruding from the base 20 of the emitter 10to provide an additional mounting for the plate 66. The two holes 68 and70 on the plate 66 are spaced such that, when the first hole 68 ispositioned over the locator peg 72, the second hole 70 is situated overthe emitter outlet 22. The copper plate 66 may be mounted to the base 20of the emitter 10 in various ways, i.e., the copper plate 66 can be heatstaked, glued, co-molded, or otherwise mounted to the base 20.Alternatively, part or all of the base 20 may be flashed with a thinprotective copper layer about the emitter outlet 22.

Two T-shaped mounts 65 located at the ends of the base 20 also arepreferably used in mounting the base 20 to the inner surface 110 of theirrigation tube 100. The T-shaped mounts 65 assist in securing theemitter 10 to the irrigation tube 100 and provide additional mountingsupport for the raised rim 28. The T-shaped mounts 65 also providestructural integrity to the emitter 10 for resisting forces exerted bywater flowing in the irrigation tube 100 and forces exerted when achimney 26 is used to create an opening in the tube wall 110. TheT-shaped mounts 65 also may be used to provide support for the coppermember 64 when the copper member 64 is compression fitted to the base20. Although the mounts 65 are shown in FIGS. 14 and 15 as T-shaped, itshould be evident that the mounts may have various other shapes, such ascircular or L-shaped, that may be used in other embodiments for mountingthe emitter 10 to the inner surface 110 of the irrigation tube 100.

The copper member 64 may take on other forms beside the copper plate 66.For instance, as shown in FIG. 16, a second form is a copper shield flap74. The copper shield flap 74 preferably includes the rectangular copperplate 66 compression fitted to the emitter base 20, such as that shownin FIGS. 14 and 15, with two holes 68 and 70 therethrough, one of whichfits over the locator peg 72 and the second of which fits over theemitter outlet 22 of FIGS. 14 and 15. As shown in FIG. 16, the copperplate 66 is folded over on itself to form a second layer 76 extendingover the emitter outlet 22. This second layer 76 provides addedprotection to the emitter outlet 22 without affecting the water flow. Italso acts as a physical barrier that protects the emitter outlet 22 fromroots extending towards the emitter outlet 22.

Another form of the copper member 64 is the copper screen shield 78shown in FIG. 17. The copper screen shield 78 is made up of woven copperstrands 80 and has a hole 82 extending therethrough, as shown in FIG.17, for positioning over the emitter outlet 22 shown in FIGS. 14 and 15.The mesh 80 forms a rectangular strip that is dimensioned to be mountedto the base 20 of the emitter 10 and to be mounted over the emitteroutlet 22. One benefit of the copper screen shield 78 is that it isflexible and easy to mount about the outlets of certain emitters. Also,because of the many openings in the screen, there is increased coppersurface area and, therefore, potentially more copper that may be takenup by an intruding plant root.

A fourth form of the copper member 64 is the copper shield L-flap 84shown in FIG. 18. One portion of the copper shield L-flap 84 is arectangular strip 86 with a hole 88 therethrough that is mounted inabutting engagement to the base 20 of the emitter 10. A second portionof the copper shield L-flap 84 is a foldable square portion 90 that isfolded over the rectangular strip 86, along the fold line 92. The strip86 is mounted so that the hole 88 is positioned over the emitter outlet22, allowing water to flow through the hole 88 of the strip 86. Whenfolded, the folded portion 90 is not in abutting engagement with thestrip 86 but, instead, forms a gap with the strip 86 so that water flowis not obstructed. The folded portion 90 extends outwardly above and infront of the emitter outlet 22, thereby providing added protection andacting as a physical barrier to root intrusion.

The preferred material for the member 64 consists of entirely, or almostentirely, copper. Copper alloy, including alloy containing 50% or morecopper, may also be used to inhibit root intrusion. Alternatively, themember 64 may include non-copper and copper portions, such as a plasticcore surrounded completely or in part by an outer copper layer. Further,as should be evident, the geometry, dimensions, and arrangement of suchcopper members 64 may vary depending on the specific shape and size ofthe subsurface drip emitter and its outlet and is not limited to thegeometry of the embodiments shown in FIGS. 14-18.

One significant advantage of the copper member 64 is that the emitteroutlets 22 are easily locatable. Subsurface drip emitters, made ofplastic, silicone, and rubber components, and buried underground, aregenerally not readily locatable from above ground. By using copper atthe emitter outlet 22 of each emitter 10, a metal detector can be usedto easily locate the exact position of emitter outlets 22 in the dripirrigation tube 100 despite the fact that the tube 100 and emitters 10are buried.

Moreover, copper installed in each emitter 10 can be located with ametal detector so that irrigation tubes 100 and emitters 10 can beeasily located years after the system is installed. For example, thisfeature helps easily locate irrigation tubes 100 underground to preventtube puncture that may result from the installation of aerationequipment, tent stakes, signs, etc. This feature also helps easilylocate irrigation tubes 100 and emitters 10 underground to accomplishmaintenance practices on the tubes 100 and emitters 10, such asreplacing pieces of tubing, changing the layout of the irrigationsystem, and replacing old emitters with new emitters having differentflow rates.

An additional advantage provided by the copper member 64 is that theprotection against intruding plant roots is not affected by non-levelterrain or relative orientation of the drip emitter 10. Chemicals usedto prevent intruding roots may run off or otherwise become distributedunevenly where the terrain is not level or where the emitter 10 isoriented in a certain manner. In contrast, the emitter outlet 22 isprotected by the copper member 64, which is affixed directly thereto,and such protection is not affected by the unevenness of the terrain orthe orientation of the emitter 10.

Another significant advantage provided by the copper member 64 is thatit does not seriously harm plants or detrimentally impact theenvironment. The copper taken up by a plant root has a localized effecton the root and does not harm the entire plant. Further, the aboveembodiments do not rely on the use of an herbicide to protect againstplant root intrusion, which may have a significant and detrimental plantand environmental impact. Instead, the above embodiments prevent rootintrusion in an environmentally friendly manner.

The foregoing relates to preferred exemplary embodiments of theinvention. It is understood that other embodiments and variants arepossible which lie within the spirit and scope of the invention as setforth in the following claims.

What is claimed is:
 1. An irrigation system comprising: a supply tubehaving an interior which is capable of supplying fluid and having a walldefining a plurality of tube outlets extending therethrough; a pluralityof drip emitters mounted to the wall within the interior of the supplytube, each drip emitter being associated with one of the plurality oftube outlets; at least one drip emitter comprising: a body defining aninlet and an outlet downstream of the inlet, the inlet receiving fluidat a first pressure and the outlet emitting fluid at a second pressure,the second pressure being less than the first pressure; a first flowpath extending through the body from the inlet to the outlet; a pressurereducing path defining a portion of the flow path between the inlet andthe outlet; the body having a mounting portion engaging the wall of thesupply tube within the interior of the supply tube to form an outletbath within the supply tube defined by a space between the body and thewall of the supply tube, the outlet bath being downstream of the outletand upstream of the associated tube outlet; and a copper containingmetal member sized to fit in the outlet bath and disposed in a secondflow path between the outlet and the associated tube outlet, the coppercontaining metal member fixed against movement in the outlet bath tomaintain at least a portion of the copper containing metal member at theoutlet; wherein a portion of the body forming the outlet bath definesthe outlet at the end of the first flow path leading into the outletbath and the copper containing metal member defines a hole aligned withthe outlet to allow water to pass through the copper containing metalmember.
 2. The irrigation system of claim 1, wherein the coppercontaining metal member is a copper containing metal plate fitted at aportion of the body forming the outlet bath.
 3. The irrigation system ofclaim 1, wherein the copper containing metal member comprises almostentirely copper.
 4. The irrigation system of claim 1, wherein the coppercontaining metal member is a non-soluble metallic copper piece.
 5. Anirrigation system comprising: a supply tube having an interior which iscapable of supplying fluid and having a wall defining a plurality oftube outlets extending therethrough; a plurality of drip emittersmounted to the wall within the interior of the supply tube, each dripemitter being associated with one of the plurality of tube outlets; atleast one drip emitter comprising: a body defining an inlet and anoutlet downstream of the inlet, the inlet receiving fluid at a firstpressure and the outlet emitting fluid at a second pressure, the secondpressure being less than the first pressure; a first flow path extendingthrough the body from the inlet to the outlet; a pressure reducing pathdefining a portion of the flow path between the inlet and the outlet;the body having a mounting portion engaging the wall of the supply tubewithin the interior of the supply tube to form an outlet bath within thesupply tube defined by a space between the body and the wall of thesupply tube, the outlet bath being downstream of the outlet and upstreamof the associated tube outlet; and a copper containing metal membersized to fit in the outlet bath and disposed in a second flow pathbetween the outlet and the associated tube outlet, the copper containingmetal member fixed against movement in the outlet bath to maintain atleast a portion of the copper containing metal member at the outlet;wherein the at least one drip emitter further comprises a protrusionprojecting from the body into the outlet bath and the copper containingmetal member defines a first hole receiving the protrusion.
 6. Theirrigation system of claim 5, wherein the copper containing metal memberdefines a second hole, the first and second holes spaced from oneanother such that the second hole aligns with the outlet when the firsthole receives the protrusion.